Wafer stuffing box

ABSTRACT

A low-profile wafer stuffing box includes a plurality of replaceable seals located within a single, unitary body. The body includes a central bore with a plurality of internal channels, a first internal channel located proximate a top surface of the body, a second internal channel located proximate a bottom surface of the body, and a third internal channel being located between the first internal channel and the second internal channel. An internal fluid corridor extends from the front wall through the stuffing box body and into the third internal channel. The low-profile wafer stuffing box may be used on reciprocating piston pumps.

FIELD OF THE DISCLOSURE

This invention relates generally to devices and methods for pumping liquids and more particularly to stuffing box seals for reciprocating piston pumps.

BACKGROUND OF THE INVENTION

There are a variety of techniques for pumping fluids from underground reservoirs. Over a hundred years ago, general windmill and hand pump systems were developed to access well water for drinking and irrigation. The devices used top head drive piston pumps and stand pipes for the fluid discharge. This basic technology, albeit in more advanced forms, is in use today. Of course today, pumping systems are used in a variety of applications and come in a variety of other forms as well.

Many modern pumping techniques, for example, are called upon to pump underground fluid in a liquid sealed manner. This is particularly useful because in many applications, such as leachate removal from a landfill, the fluids being pumped can be hazardous to people and the environment. As a result, modern pumping systems often include mechanisms that prevent leakage.

Modern reciprocating piston pumps used to pump wells generally include a reciprocatable sucker rod having a piston at one end, where the sucker rod and piston are disposed in a riser pipe. As the sucker rod and piston reciprocate within the riser pipe, liquid is pumped up the riser pipe by the piston and ultimately to the ground for discharge. Actuators are used to move the sucker rod within the riser pipe. The actuator may be attached to a stand pipe surrounding the riser pipe. The actuator may include an actuator rod that is moved within the actuator by electrical, mechanical, or pneumatic means. The actuator rod is connected to the sucker rod via a rod connector.

To prevent leakage, known pumping systems use a stuffing box mounted near the top of the ground seal for the well. The stuffing box forms a seal between the sucker rod and the actuator housing to prevent pumped fluid from spilling onto the ground or seeping into the actuator via the actuator rod.

Stuffing box designs, however, can fail to give long enough seal lifetimes. Seal failures occur too frequently, especially where pumps are used to pump against substantial back pressure (liquid head pressure) and where pumps are used to pump fluid with substantial amounts of grit or other contaminants.

Many stuffing box designs suffer from short life times and replacement problems. For example, stuffing boxes that use packing gland materials for sealing are problematic because of the constant need to readjust the packing material. In these devices, materials like graphite impregnated twine (plumber's oakum) or slant split rubber bo-rings are used as the packing material, screwed down in the stuffing box by a packing gland nut to create a liquid tight seal against the drive rod. The packing material has to be compressed just right to form a tight seal. However, if the material is too compacted, the material may squeeze against the drive rod and cause stalling of the pumping system. If the packing material is too loose, fluid leakage will occur.

Moreover, the reciprocating action of the sucker rod in the riser pipe will wear on the packing material, unpacking the material and necessitating replacement of the stuffing box assembly or finding some way of re-packing the packing material into the desired, operable range.

Furthermore, it is time consuming to change out many of the current stuffing box designs. In order to change the stuffing box, or the seals within the stuffing box, the actuator must be disconnected from the well head and the actuator rod must be disconnected from the sucker rod at the rod connector and the rod connector must be removed from the actuator rod. Finally, the stuffing box may be slid off of the actuator rod and replaced with a new stuffing box, or the seals in the old stuffing box are replaced with new seals. Assembly occurs in the reverse.

Due to these problems, previous attempts to extend the service life of the stuffing boxes have been made. Most of these attempts have involved adding more seals to the stuffing box. Some stuffing boxes now include 4 or more seals. However, simply adding more seals to the stuffing box has not significantly extended the service life of most known stuffing boxes.

SUMMARY OF THE INVENTION

A low-profile wafer stuffing box includes a plurality of replaceable seals located within a single, unitary body. The body includes a central bore with a plurality of internal channels, a first internal channel located proximate a top surface of the body, a second internal channel located proximate a bottom surface of the body, and a third internal channel being located between the first internal channel and the second internal channel. An internal fluid corridor extends from the front wall through the stuffing box body and into the third internal channel.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side sectional view of a piston pump constructed in accordance with teachings in the disclosure;

FIG. 2 is a close up side sectional view of the actuator, a wafer stuffing box, and the discharge tee of the piston pump of FIG. 1;

FIG. 3 is a side exploded view of the actuator of the piston pump of FIG. 1;

FIG. 4 is a bottom perspective view of the wafer stuffing box of FIG. 2;

FIG. 5 is a top plan view of the wafer stuffing box of FIG. 2;

FIG. 6 is a side cross-sectional view of the wafer stuffing box of FIG. 2;

FIG. 6A is a close up of an internal channel of the wafer stuffing box of FIG. 6;

FIG. 7 is a cross-sectional view of the wafer stuffing box of FIG. 6 including replaceable seals disposed in internal channels of the wafer stuffing box;

FIG. 8 is a cross-sectional view of the wafer stuffing box of FIG. 2 disposed on the actuator rod of the piston pump of FIG. 1 with the actuator rod being coupled to a sucker rod with a compression rod connector;

FIG. 9A is a bottom plan view of one of the replaceable seals of FIG. 7, in particular, a scraper seal;

FIG. 9B is a cross-sectional view of the scraper seal of FIG. 9A;

FIG. 10 A is a top plan view of another one of the replaceable seals of FIG. 7, in particular, a rod wiper seal; and

FIG. 10B is a cross-sectional view of the rod wiper seal of FIG. 10A.

DETAILED DESCRIPTION

FIG. 1 illustrates one example of a piston pump 100 constructed in accordance with the teachings of the disclosure. The piston pump 100 includes a riser pipe 102 and a valve assembly 104 attached to one end of the riser pipe 102. The valve assembly 104 includes a piston 106 connected to a drive or sucker rod 108. The sucker rod 108 may be made of fiberglass, metal, or any other suitable material. The sucker rod 108 extends through a flow chamber 110 in the riser pipe 102 and the sucker rod 108 is movable in a reciprocating motion through the flow chamber 110 thereby causing the piston 106 to also move in a reciprocating motion, which pumps liquid in a direction from the valve assembly 104 towards a discharge tee 112. The discharge tee 112 may be connected to a pipeline (not shown) for transportation of the liquid to a treatment site or collection system.

A motor 114 is operatively connected to the sucker rod 108 by an actuator 116 having an actuator rod 120. Limit switches 118 may measure movement (e.g., count numbers of strokes) of the actuator rod 120 as the motor 114 moves the actuator rod 120. The limit switches 118 may send signals to a controller (not shown) as the actuator rod 120 passes by the limit switches 118 so that the controller knows the location of the actuator rod 120. The controller sends signals to the motor 114 based on input from the limit switches 118 and a programmed operational routine, thereby controlling the frequency and direction that the motor 114 moves the actuator rod 120, and thus the sucker rod 108 and piston 106. The actuator rod 120 and the sucker rod 108 may be attached to one another with a connection fitting 121 (FIG. 2). The motor 114 may be a variable speed motor to move the actuator at different speeds and/or frequencies. The motor 114 may be electrically or pneumatically actuated.

A yoke 124 (FIG. 2) connects the actuator 116 to the discharge tee 112, which is connected to a well head 122. The yoke 124 may include a top plate 126 and a bottom plate 128 separated by one or more pillars 130. The pillars 130 keep the top and bottom plates 126, 128 separated, thereby forming a space 132 that accommodates a wafer stuffing box 134. The space 132 is large enough to accommodate a plurality of stacked wafer stuffing boxes if desired. The wafer stuffing box 134 seals fluid within the flow corridor 110 from the inside of the actuator 116. The wafer stuffing box 134 may include one or more seals (as set forth hereinafter) that scrape fluid off of, or otherwise seal fluid from, the actuator rod 120 before the fluid can enter into the actuator housing 136, thereby protecting internal components of the actuator 116 from any harmful characteristics of the fluid.

FIG. 3 illustrates a fragmented view of the actuator 116. The actuator housing 136 is located between a motor coupling 138 and a bottom plate 140. The bottom plate 140, in turn, is coupled to the yoke 124 (FIG. 2). A bearing housing 142 including a zerk fitting 144 is located near the top of the actuator housing 136, proximate the motor coupling 138. The zerk fitting 144 forms a sealable passage for lubrication of a thrust bearing 145. The motor coupling 138, bearing housing 142, actuator housing 136, and bottom plate 140 may be attached to one another via virtually any means of attachment, such as, for example, fasteners 146, welding, adhesive, etc. Inner components of the actuator 116 include a coupling device 148 comprising a coupling sleeve 150, a top shear coupling 152 a and a bottom shear coupling 152 b. The coupling device 148 connects a ball screw 154 to the motor 114 so that the ball screw 154 rotates as the motor 114 turns. The shear couplings 152 a, 152 b provide safety protection for the actuator in that the shear couplings 152 a, 152 b are designed to fail before the motor 114 or actuator rod 120 should the sucker rod 108 or actuator rod 120 become stuck. A ball screw nut 156 rides longitudinally along the ball screw 154 as the ball screw 154 rotates. The ball screw nut 156 is threadedly connected to the ball screw 154. The ball screw nut 156 is attached to an anti-rotation block 158, which prevents the actuator rod 120 from rotating with the ball screw 154. Instead, the rotation of the ball screw 154 is transformed into linear motion via the ball screw nut 156 and the anti-rotation block 158 so that the actuator rod 120 reciprocates longitudinally within the actuator 116 as the ball screw 154 rotates.

FIG. 4 illustrates one embodiment of a wafer stuffing box 134 constructed in accordance with the teachings of the disclosure. The wafer stuffing box 134 includes a body forming a rectangular box shape in this embodiment. However, other shapes are possible, such as, for example, cylindrical (having any cross-sectional shape, such as, circular, oval, square, rectangular, polygonal, etc), irregular, etc. The wafer stuffing box 134 body includes a top surface 160, a bottom surface 162, a front wall 166, a rear wall 168, and two side walls 164. The wafer stuffing box 134 also includes one or more apertures 170 for receiving fasteners to attach the wafer stuffing box 134 to the bottom plate 128 of the yoke 124 (FIG. 2). A central opening 172 extends through the wafer stuffing box 134 from the top surface 160 to the bottom surface 162. The central opening 172 is sized to receive the actuator rod 120 (FIG. 3). The central opening 172 includes one or more internal channels 174 for receiving seal assemblies, or to provide lubrication, as will be discussed further hereinafter. The bottom surface 162 also may include a circular resilient seal 176. The resilient seal 176 may take on virtually any shape, such as, for example, circular, oval, rectangular, polygonal, etc. The resilient seal 176 is seated within an external channel 178 formed in the bottom surface 162 of the wafer stuffing box 134. The resilient seal 176 forms a seal between adjacent wafer stuffing boxes 134 when a plurality of wafer stuffing boxes 134 are stacked within the yoke 124.

FIGS. 5, 6, and 6A illustrate various parts of the wafer stuffing box 134 of FIG. 4. In particular, FIG. 6 illustrates three internal channels 174 a, 174 b, 174 c. Other embodiments may include more or less than three internal channels. In the illustrated example, internal channels 174 a and 174 c are configured to secure a seal (discussed further hereinafter) within the internal channels 174 a, 174 c respectively. Internal channel 174 b is fluidly connected to the zerk fitting 144, for example the internal channel 174 b may be connected to the zerk fitting 144 via an internal corridor 180 (FIG. 5). During operation, a maintenance technician can lubricate the wafer stuffing box 134 by forcing a lubricant through the zerk fitting 144, into the internal corridor 180, and into the internal channel 174 b. The lubricant may be held between the seals disposed in internal channels 174 a and 174 c, thus enhancing the sealing ability of the wafer stuffing box 134. Moreover, certain lubricants may provide a protective coating to protect the actuator rod 120 against corrosion, impingement damage, or other harm. Keeping the actuator rod 120 smooth and in good condition lengthens seal life because rough actuator rods 120 have been observed to shorten seal life by snagging and tearing the seals during actuation of the actuator rod 120.

The bottom internal channel 174 c may include an internal shelf 182 and a chamfered portion 184 (FIG. 6A). The chamfered portion 184 may serve to align a seal during insertion into the bottom internal channel 174 and the internal shelf 182 helps to secure the seal in the bottom internal channel 174. The chamfered portion 184 may take on virtually any angle, the angle preferred to be in the range of approximately 10° and approximately 80°, and highly preferred to be in the range of approximately 15° and approximately 45°.

The wafer stuffing box 134 of FIGS. 4-6A is approximately 4⅝ inches long, approximately 3 inches wide, and approximately 1 inch high. The central opening 172 has a larger diameter D1 (FIG. 7) proximate the top surface 160, and a smaller diameter D2 between the top internal channel 174 a and the bottom internal channel 174 c. In the embodiment of FIG. 7, the larger diameter is approximately 1.135 inches and the smaller diameter is approximately 1.001 inches. The larger diameter D1 allows a seal disposed in the top internal channel 174 a to flex and rotate somewhat during actuation of the actuator rod 120 in order to wipe the actuator rod 120 clean of any remaining fluid and/or lubricant. The smaller diameter D2 helps to contain lubricant within the internal channel 174 b, while simultaneously keeping the actuator rod 120 precisely centered within the central opening 172. Of course, the dimensions herein with respect to FIG. 4 are exemplary only. Those skilled in the art may size the wafer stuffing box 134 as needed for any particular operation.

The disclosed wafer stuffing box 134 advantageously results in a relatively low-profile housing. In particular, in the example disclosed in FIGS. 4-7, the low-profile body has a thickness that is less than or equal to a diameter of the central opening 172. In the particular example disclosed in FIGS. 4-7, each of the front, rear, and side walls 166, 168, 164 has a height (as illustrated in FIGS. 6 and 7) that is less than or equal to either diameter (D1 or D2) of the central opening 172. As a result, the disclosed wafer stuffing box 134 requires a smaller yoke 124 and/or a plurality of the disclosed wafer stuffing boxes may be stacked one upon another within a standard sized yoke 124.

An additional advantage of the disclosed wafer stuffing box 134 is that all of the replaceable seals (e.g., scraper seal 186 and rod wiper seal 188) are located within a single, unitary wafer stuffing box body. This configuration results in fewer parts to manufacture and stock. Thus, the disclosed wafer stuffing box 134 is less expensive to manufacture and less costly to stock as inventory.

Moreover, the disclosed wafer stuffing box 134 has a sealing ability that meets or exceeds the sealing ability of prior art stuffing boxes while using fewer internal seals (e.g., the scraper seal 186 and the rod wiper seal 188). As a result, manufacturing costs are significantly reduced.

FIG. 7 illustrates a cross-sectional view of an example of the wafer stuffing box 134 with a scraper seal 186 disposed in the bottom internal channel 174 c and a rod wiper seal 188 disposed in the top inner channel 174 a. The scraper seal 186 and the rod wiper seal 188 are further described with respect to FIGS. 9 and 10.

The scraper seal 186 may be desirably formed of a semi-stiff, yet flexible material such as, for example, Teflon®, plastic, Buna Nitrile, Viton®, polyurethane, etc. The scraper seal 186 has an inner diameter 186 i and an outer diameter 186 o. A central bore forms an inner cylindrical surface 190. The scraper seal 186 also includes an outer cylindrical surface 192. Between the inner cylindrical surface 190 and the outer cylindrical surface 192 is an inverted scraper channel 194. The inverted scraper channel 194 includes an angled inner surface 196 beginning at a bottom side of the scraper seal 186 and joining the inner cylindrical surface 190 forming a sharp scraping point 191. The sharp scraping point 191 scrapes fluid off of the actuator rod 120, funneling removed fluid into the inverted channel 194. An outer angled surface 198 beginning at the bottom side of the scraper seal 186 joins the outer cylindrical surface 192. The inner and outer angled surfaces 196, 198 are joined by a channel floor 200 that in the embodiment of FIGS. 9A and 9B is substantially perpendicular to the inner and outer cylindrical surfaces 190, 192. To enhance the stiffness of the scraper seal 186, thereby maintaining the sharp scraping point 191 in contact with the actuator rod 120, and to prolong the useful life of the scraper seal 186, a semi-rigid insert 202 is disposed within the scraper channel 194. In one embodiment, the semi-rigid insert 202 may be a segmented metal ring made of, for example, brass or any other metal that is softer than chrome plated stainless steel. However, the semi-rigid insert 202 may be formed from virtually any semi-rigid material. The semi-rigid insert 202 especially stiffens the inner cylindrical surface 190 to maintain a solid interface between the scraper seal 186 and the actuator rod 120.

Like the scraper seal 186, the rod wiper seal 188 includes an inner cylindrical surface 204 and an outer cylindrical surface 206. However, unlike the scraper seal 186, the inner cylindrical surface 204 is longer than the outer cylindrical surface 206 along a longitudinal axis of the rod wiper seal 188. An exterior of the rod wiper seal 188 includes a ledge 208 and an angled surface 210 connecting the inner cylindrical surface 204 to the ledge 208. Like the scraper seal 186, the rod wiper seal 188 includes an inverted wiper channel 212 on a bottom side of the rod wiper seal 188. However, unlike the scraper seal 186, the inverted wiper channel 212 does not have a channel floor. Rather, the inverted wiper channel 212 includes an inner angled surface 214 and an outer angled surface 216 that meet in a center of the inverted wiper channel 212, thereby forming an inverted v-shape in the cross-section. The rod wiper seal 188 may be formed of any substantially resilient material such as, for example, Buna Nitrile, Viton®, Teflon®, plastic, etc.

Returning now to FIG. 8, the wafer stuffing box 134 is illustrated as being mounted on the actuator rod 120. Some elements, such as the yoke 124 are omitted for clarity in this Figure. The actuator rod 120 is attached to the sucker rod 108 via the connection fitting 121. As the actuator rod 120 reciprocates towards the motor (not shown, upward in FIG. 8), the scraper seal 186 scrapes fluid off of the external surface of the actuator rod 120 via the sharp scraping point 191. The actuator rod 120 may be lubricated if any lubricant is disposed in inner channel 174 b. Finally, the rod wiper seal 188 wipes any lubricant and/or remaining fluid off of the actuator rod 120 before that portion of the actuator rod 120 moves into the actuator housing. Due to friction between the actuator rod 120 and inner cylindrical surface 204 of the rod wiper seal 188, the rod wiper seal 188 may pivot slightly, to allow a top of the rod wiper seal 188 to move radially outward as the actuator rod 120 ascends. This movement may cause the inverted channel 212 to expand slightly, forcing an edge of the inverted channel 212 and the inner cylindrical surface 204 into firm contact with the actuator rod 120. This movement angles the edge between the inverted channel 212 and the inner cylindrical surface 204 into the actuator rod 120, thereby enhancing wiping of the actuator rod 120 and forcing any fluid or lubricant removed from the actuator rod 120 into the inverted channel 212.

During removal of the wafer stuffing box 134, for replacement of the seals, for example, the sucker rod 108 is disconnected from the connection fitting 121. After the sucker rod 108 is disconnected, the wafer stuffing box 134 will slide off of the end of the actuator rod 120, and over the connection fitting 121 because the outer diameter of the actuator rod 120 is greater than, or equal to, the outer diameter of the connection fitting 121. Thus, the disclosed wafer stuffing box 134 is an improvement over prior art stuffing boxes, which required removal of the connection fitting 121 from the actuator rod 120 prior to removing the stuffing box because the connection fitting was larger than the diameter of the actuator rod 120.

Unlike known stuffing boxes that include packing gland material, the disclosed wafer stuffing box 134 does not include the packing gland material that is forced out of an opening in order to seal the actuator rod. Thus, the disclosed wafer stuffing box 134 does not require a tightening mechanism to squeeze packing gland material of an opening in the stuffing box body. As a result, the disclosed wafer stuffing box 134 does not suffer from problems of over-tightening (which induces unnecessary drag and friction on the actuator rod causing premature failure of the stuffing box, actuator rod, or motor), uneven tightening (which can cause misalignment of the actuator rod), and constant readjustment due to packing gland material loss. Moreover, the disclosed wafer stuffing box 134 centers more easily than known stuffing boxes during installation, thus reducing uneven side wear of the actuator rod or replaceable seals.

Although certain piston pumps and stuffing boxes have been described herein in accordance with the teachings of the present disclosure, the scope of the appended claims is not limited thereto. On the contrary, the claims cover all embodiments of the teachings of this disclosure that fairly fall within the scope of permissible equivalents. 

1. A reciprocating piston pump comprising: a riser pipe; a well head attached to the riser pipe; a sucker rod disposed within the riser pipe and extending through the well head, the sucker rod having a piston attached thereto; an actuator having an actuator rod operatively coupled to a ball screw, at least a portion of the ball screw being disposed within the actuator rod; a motor connected to the actuator and operatively coupled to the ball screw, the motor rotating the ball screw within the actuator rod; and a wafer stuffing box disposed between the well head and the actuator, the wafer stuffing box including a stuffing box body and a central bore running through the stuffing box body, the central bore including an internal channel; wherein the actuator rod is connected to the sucker rod by a connection fitting, the actuator rod having an outer diameter that is greater than or equal to an outer diameter of the connection fitting, and the central bore has an inner diameter that is substantially equal to the outer diameter of the actuator rod.
 2. The reciprocating piston pump according to claim 1, further comprising a plurality of inner channels within the central bore of the wafer stuffing box.
 3. The reciprocating piston pump according to claim 1, wherein one side of the wafer stuffing box body comprises a recessed channel.
 4. The reciprocating piston pump according to claim 3, further comprising a resilient seal disposed in the recessed channel.
 5. The reciprocating piston pump according to claim 1, further comprising a seal disposed in the inner channel.
 6. The reciprocating piston pump according to claim 1, wherein the wafer stuffing box includes a zerk fitting fluidly connected to an internal corridor, the internal corridor being fluidly connected to the internal channel for transferring a lubricant into the central bore.
 7. The reciprocating piston pump according to claim 1, comprising a plurality of inner channels in the central bore.
 8. A low-profile wafer stuffing box for a reciprocating piston pump, the low-profile wafer stuffing box comprising: a stuffing box body having a first side, a second side, a front wall, a rear wall, and a pair of side walls; a central bore extending through the stuffing box body from the first side to the second side; a plurality of internal channels within the central bore, a first seal disposed in a first internal channel and a second seal disposed in a second internal channel, a third internal channel being disposed between the first internal channel and the second internal channel; an internal fluid corridor extending from the front wall through the stuffing box body and into the third internal channel.
 9. The reciprocating piston pump according to claim 8, wherein the one of the first and second seals comprises an inverted channel.
 10. The reciprocating piston pump according to claim 9, wherein the inverted channel comprises two angled sidewalls connected by a channel floor.
 11. The reciprocating piston pump according to claim 10, wherein the channel floor is oriented substantially perpendicular to a longitudinal axis of the central bore.
 12. The reciprocating piston pump according to claim 10, further comprising a semi-rigid insert disposed in the inverted channel.
 13. The reciprocating piston pump according to claim 12, wherein the semi-rigid insert comprises a segmented metal ring.
 14. The reciprocating piston pump according to claim 9, wherein the inverted channel comprises a pair of angled sidewalls that meet in a center of the inverted channel.
 15. The reciprocating piston pump according to claim 14, further comprising an outer shelf connected to an angled surface, the outer shelf being oriented substantially perpendicular to a longitudinal axis of the wafer stuffing box.
 16. The reciprocating piston pump according to claim 8, further comprising a recessed channel on one side of the stuffing box body.
 17. The reciprocating piston pump according to claim 16, wherein the first internal channel includes a rod wiper seal and the second internal channel includes a scraper seal.
 18. The wafer stuffing box of claim 16, further comprising a resilient seal disposed within the recessed channel.
 19. The wafer stuffing box of claim 18, further comprising a zerk fitting disposed on the front wall, the zerk fitting being fluidly connected to the internal fluid corridor.
 20. A wafer stuffing box for a reciprocating piston pump, the wafer stuffing box comprising: a body including a top side, a bottom side, a front wall, a rear wall, and a pair of side walls; a central opening extending through the body from the top side to the bottom side; a plurality of internal channels disposed within the central opening, a first internal channel being located near the top side of the body, a second internal channel being located near a bottom side of the body, and a third internal channel being located between the first and second internal channels; an internal corridor extending from the front side to the third internal channel, the internal corridor being capable of transporting a lubricant into the third internal channel; a rod scraper seal disposed in the second internal channel, the rod scraper seal including an inner cylindrical surface, an outer cylindrical surface, and an inverted scraper channel on a bottom of the rod scraper seal between the inner cylindrical surface and the outer cylindrical surface; a semi-rigid insert disposed within the inverted scraper channel; a rod wiper seal disposed in the first internal channel, the rod wiper seal including an inner cylindrical surface and an outer cylindrical surface, the inner cylindrical surface being longer than the outer cylindrical surface along a longitudinal axis of the rod wiper seal, an outer ledge connected to a top end of the outer cylindrical surface, and an angled surface connecting the outer ledge to the inner cylindrical surface; an external channel disposed on the bottom side of the body, the external channel surrounding the central opening; and a resilient seal disposed within the external channel. 